Can you tell the difference between cellophane and fiberglass paper?
1) Fiberglass Paper
Fiberglass paper is an industrial paper, generally used as a filter material, sound-absorbing material, heat insulation material, and electrical insulation material. It is a paper sheet made from fine glass fibers, possessing high flame retardancy, strong chemical resistance, and good dimensional stability.
The manufacturing process of this paper differs slightly from ordinary papermaking. It uses 100% glass fiber (mainly silica, with a diameter of less than 0.3-0.5 μm), lightly pulped, with the addition of adhesives, or sometimes a portion of chemical wood pulp, and formed on a fourdrinier or cylinder paper machine. Silica gel or colloidal alumina can also be added to improve the strength of the finished paper.
The production process of glass fiber paper (or glass fiber air filter paper) is relatively simpler than the general papermaking process. This is because glass fibers do not require pulping, only dispersion. Furthermore, pressing is not required during papermaking, reducing steps and saving energy.
The process flow is as follows: Glass fiber → Dispersion → Slurry storage tank → Slurry pump → Pre-slurry tank → Slurry conditioning tank → Settling pan → Slurry flushing tank → Slurry pump → Slurry stabilizing tank → Headbox → Wire section → Drying oven → Winding → Slitting and packaging
2) Cellophane
Cellophane is a highly transparent, glossy regenerated cellulose film, formerly known as celluloid, a transliteration of the English word "cellophane." It is a type of paper used for product packaging, belonging to the category of packaging paper. Note that there is also a term called "celluloid," which is not paper but a type of nitrocellulose plastic (the raw material for making ping-pong balls). Celluloid is a transliteration of the English word "celluloid." The two should not be confused.
Cellophane's basis weight is generally 30-60 g/m². It is available in sheets and rolls. It is typically a colorless, transparent, smooth, thin sheet, without pores, impermeable to air, oil, and water; it has a certain degree of stiffness; and possesses good tensile strength, gloss, and printability. It can also be dyed in various colors (red, yellow, etc.).
Cellophane is made of regenerated cellulose, and the gaps between its molecular groups create a unique permeability, which is beneficial for protecting and preserving goods. It is not fire-resistant but heat-resistant, remaining undeformed at 190℃, and can be used in food packaging for high-temperature sterilization along with food. Because cellophane's raw materials are derived from natural sources, it is highly biodegradable, resulting in minimal environmental impact.
Cellophane is made from refined chemical wood pulp or cotton linter dissolving pulp with a high α-cellulose content. The process involves alkalization (18% sodium hydroxide), pressing, and pulverization to obtain alkali cellulose. After aging, carbon disulfide is added to xanthate it into cellulose xanthate, which is then dissolved in sodium hydroxide solution to produce an orange-yellow cellulose viscose. This viscose is cured at 20–30℃, filtered to remove impurities and air bubbles, and then extruded through a narrow slit in a film stretching machine. The film flows into a coagulation bath containing a mixture of sulfuric acid and sodium sulfate to form a film (regenerated cellulose film). This film then undergoes washing, desulfurization, bleaching, desalting, and plasticizing (with glycerol and ethylene glycol, etc.), and is finally dried.
